diff --git a/src/vs/vscode.d.ts b/src/vs/vscode.d.ts
index 4c0ad9937a9..3a82d471f90 100644
--- a/src/vs/vscode.d.ts
+++ b/src/vs/vscode.d.ts
@@ -6883,9 +6883,10 @@ declare module 'vscode' {
 		shellPath?: string;
 
 		/**
-		 * Args for the custom shell executable, this does not work on Windows (see #8429)
+		 * Args for the custom shell executable. A string can be used on Windows only which allows
+		 * specifying shell args in [command-line format](https://msdn.microsoft.com/en-au/08dfcab2-eb6e-49a4-80eb-87d4076c98c6).
 		 */
-		shellArgs?: string[];
+		shellArgs?: string[] | string;
 
 		/**
 		 * A path or Uri for the current working directory to be used for the terminal.
diff --git a/src/vs/workbench/api/electron-browser/mainThreadTerminalService.ts b/src/vs/workbench/api/electron-browser/mainThreadTerminalService.ts
index 8a1fc7d216d..ec4551f380b 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadTerminalService.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadTerminalService.ts
@@ -59,7 +59,7 @@ export class MainThreadTerminalService implements MainThreadTerminalServiceShape
 		// when the extension host process goes down ?
 	}
 
-	public $createTerminal(name?: string, shellPath?: string, shellArgs?: string[], cwd?: string | UriComponents, env?: { [key: string]: string }, waitOnExit?: boolean, strictEnv?: boolean): Promise<{ id: number, name: string }> {
+	public $createTerminal(name?: string, shellPath?: string, shellArgs?: string[] | string, cwd?: string | UriComponents, env?: { [key: string]: string }, waitOnExit?: boolean, strictEnv?: boolean): Promise<{ id: number, name: string }> {
 		const shellLaunchConfig: IShellLaunchConfig = {
 			name,
 			executable: shellPath,
diff --git a/src/vs/workbench/api/node/extHost.protocol.ts b/src/vs/workbench/api/node/extHost.protocol.ts
index 2ba6a6edd93..5c7d2669b7f 100644
--- a/src/vs/workbench/api/node/extHost.protocol.ts
+++ b/src/vs/workbench/api/node/extHost.protocol.ts
@@ -371,7 +371,7 @@ export interface MainThreadProgressShape extends IDisposable {
 }
 
 export interface MainThreadTerminalServiceShape extends IDisposable {
-	$createTerminal(name?: string, shellPath?: string, shellArgs?: string[], cwd?: string | UriComponents, env?: { [key: string]: string | null }, waitOnExit?: boolean, strictEnv?: boolean): Promise<{ id: number, name: string }>;
+	$createTerminal(name?: string, shellPath?: string, shellArgs?: string[] | string, cwd?: string | UriComponents, env?: { [key: string]: string | null }, waitOnExit?: boolean, strictEnv?: boolean): Promise<{ id: number, name: string }>;
 	$createTerminalRenderer(name: string): Promise<number>;
 	$dispose(terminalId: number): void;
 	$hide(terminalId: number): void;
diff --git a/src/vs/workbench/api/node/extHostTerminalService.ts b/src/vs/workbench/api/node/extHostTerminalService.ts
index 9bb24ef880d..7d623816219 100644
--- a/src/vs/workbench/api/node/extHostTerminalService.ts
+++ b/src/vs/workbench/api/node/extHostTerminalService.ts
@@ -106,7 +106,7 @@ export class ExtHostTerminal extends BaseExtHostTerminal implements vscode.Termi
 
 	public create(
 		shellPath?: string,
-		shellArgs?: string[],
+		shellArgs?: string[] | string,
 		cwd?: string | URI,
 		env?: { [key: string]: string | null },
 		waitOnExit?: boolean,